| 摘要 |
PURPOSE:To make an optional call of plural terminals possible, by providing plural lines in the data link where plural terminals are connected in a loop and by using one line of them only for sending information and by connecting speakers to this line in all terminals. CONSTITUTION:Plural terminals A-E are connected in a loop by plural order wires 11a-11n. Order wires 11a-11n are defined as #0-#n lines, and the #0 line is idle. Speakers 13a-13e are always connected to this line. When a terminal wants to call, the terminal uses the #0 line to designate one of rest #1-#n lines to the destination. For example, when the call equipment is connected to the #1 line, which is designated by the terminal A, in the terminal D, the call between terminal A and D is possible through the #1 line. If another terminal wants to call, the terminal uses the #0 line similarly and sends information by speakers to designate and idle line, for example, the #2 line and calls through this line. |
